January 15-19, 2011
Town & Country Convention Center
San Diego, CA
David A Lightfoot
Genomes segmented between highly conserved and rapidly diploidized regions following increases in ploidy represent a frontier for genome analysis. Many soybean QTL analyzed to date have been composed of gene clusters each with contributing a portion of the trait rather than alleles of single genes. At the Soybean Genome Database (SoyGD) http://soybeangenome.siu.edu the genome browser that integrates and served the publicly available soybean physical map, BAC fingerprint database and genetic map associated genomic data showed two different minimum tile of transformation ready BIBAC-like clones in pCLD04541 (pV41; oriV; tra; bom). In MTP4 there were 3,840 MTP clones that encompassed 90% of the genome (see http://soybeangenome.siu.edu/cgi-bin/gbrowse/BES_scaffolds). The BIBAC-like clones (tetR) from E. coli DH10 B were transferred en masse to Agrobacterium tumefaciens by triparental matings with EHA105 (rifR) mediated by pRK2013 (oriP) in DH10B (kanR) in 384 well plates. Rifampicin and tetracyclin resistant strain mixtures were used for transformation of Arabidopsis thaliana flowers in 384 well arrays. Initially kanamycin selection was used to isolate transgenic plants. Partial transconjugation events mean only some inserts are transferred completely while other transformed lines contain a substitution series of deleted inserts anchored on the Ti-left border (LB). These are maintained as kanR mixtures of seed. Phenotypes found for lines transgenic for particular BACs that were repeated include nitrogen use efficiency, water use efficiency, seed composition (protein, oil), development (growth, senescence) and disease resistance (SDS, SCN)among a 0.4-0.8% of plant lines. Detailed analysis of plant lines transformed with BACs encompassing two homeologous regions showed one inhibited growth whilst the other promoted biomass growth. DNA sequence annotation, insert size and transgene expression analysis data identified genes in one BAC that were associated with growth inhibition whilst the other BAC the syntenic genes always promoted growth. Epigenetic signatures for gene silencing were inferred within the BACs that may be altering growth and development of A. thaliana.